This investigation sets in motion a developmental longitudinal project examining the constructs of infant coping and mastery motivation as developmental mediators of competence. It is proposed that by focusing on these constructs, it will be possible to improve prediction of general competence/dysfunction and chart more informative developmental pathways across the transition from infancy to toddlerhood in a low-income sample. The research is driven by an ecological view of human development and of the influence of family processes on developmental outcomes. According to this perspective, motivation and competence evolve from the interplay between infant and parent resources, relationship quality, and the larger familial and extrafamilial ecological context. One hundred infants (50 male, 50 female) and their mothers, representing the normal range of infant and family functioning in a low-income population, will be observed and assessed in the laboratory at the infant ages of 12, 18, and 24 months and in their home within two weeks of the 18-month lab visit. The resulting data will be used to explore individual differences in infant coping and mastery motivation, their stability over time, their ecological correlates, and concurrent and predictive relations with infant developmental competence. The ultimate data analytic goal will be to construct and test alternative models of causal influence, using carefully selected indices of parent and family resources, relationship and caregiving quality, and infant behaviors. These models will make it possible to test the usefulness of including infant coping and mastery strategies as predictors of subsequent competence among a population at ecological risk.